Every major city has a symbolic piece of architecture that projects its image to the world. But what happens when a city loses its trademark icon? This was exactly the problem that faced Malmo in Sweden - but it came up with the perfect way to reinvent itself. The city decided to build a radical skyscraper, created by one of the world's most innovative architects, Santiago Calatrava. But daring design always courts controversy - and the whole project very nearly ended in disaster.